The neural basis of dysfunctional beliefs in non-medicated patients with obsessive-compulsive disorder.

Dysfunctional beliefs may contribute to the development and maintenance of obsessive-compulsive disorder (OCD) according to some cognitive theories. As little has been investigated about the pathophysiology of dysfunctional beliefs in OCD, this study aimed to determine the anatomical regions that are related to OCD-related dysfunctional beliefs. We first examined 23 non-medicated patients with OCD by magnetic resonance imaging (MRI) and assessed their dysfunctional beliefs using the Obsessive Beliefs Questionnaire-44 (OBQ-44). OBQ-44 has three factors: (1) inflated personal responsibility and the tendency to overestimate threat (OBQ-RT), (2) perfectionism and intolerance of uncertainty (OBQ-PI), and (3) over-importance and over-control of thoughts (OBQ-IC). Voxelwise analysis was used to investigate the correlation between whole brain gray matter volume and each score of OBQ-44 covarying for age, gender, education, severity, and intracranial volume. We found a significant negative correlation between gray matter volume and OBQ-IC scores in the left amygdala; there was no significant correlation with other scores. Comparison of the amygdala volume between patients with OCD and 23 matched healthy controls indicated no volume difference between groups. Taken together, the left amygdala volume may play a role in the presence of certain dysfunctional beliefs in OCD patients.